import time

import threading

class CacheInvalidator:

def __init__(self, timeout):

self.timeout = timeout

self.cache = {}

self.lock = threading.Lock()

def invalidate(self, key):

"""Invalidates the cache entry for the given key."""

with self.lock:

if key in self.cache:

del self.cache[key]

print(f"Invalidated cache entry for key: {key}")

return True

else:

return False

def is_valid(self, key):

"""Checks if the cache entry for the given key is still valid."""

with self.lock:

if key in self.cache:

if time.time() - self.cache[key]['timestamp'] < self.timeout:

return True

else:

del self.cache[key]

print(f"Cache entry for key: {key} expired.")

return False

else:

return False

def set(self, key, value):

"""Sets a cache entry with a timestamp."""

with self.lock:

self.cache[key] = {'value': value, 'timestamp': time.time()}